US researchers have proposed a hybrid energy concept that they claim will be able to produce power around the clock by combining solar generation with hydrogen production and storage.
The so-called “Hydricity” concept, devised by a team from Purdue University, Illinois, uses solar concentrators to focus sunlight and superheat water to operate a series of electricity-generating steam turbines and reactors for splitting water into hydrogen and oxygen.
“In the round-the-clock process we produce hydrogen and electricity during daylight, store hydrogen and oxygen, and then when solar energy is not available we use hydrogen to produce electricity using a turbine-based hydrogen-power cycle,” explained Purdue’s Professor Mohit Tawarmalani.
The system – which is detailed in the Proceedings of the National Academy of Sciences – has so far just been simulated using models, but according to the team it could be far more efficient than many other energy storage systems.
“The overall sun-to-electricity efficiency of the hydricity process, averaged over a 24-hour cycle, is shown to approach 35 percent, which is nearly the efficiency attained by using the best photovoltaic cells along with batteries,” said Purdue researcher Emre Gençer. “Our proposed process stores energy thermo-chemically more efficiently than conventional energy-storage systems,” he added, “the coproduced hydrogen has alternate uses in the transportation-chemical-petrochemical industries, and unlike batteries, the stored energy does not discharge over time and the storage medium does not degrade with repeated uses.”